Wall insulation boards with non-halogenated fire retardant and insulated wall systems

ABSTRACT

According to one embodiment, a halogen free wall system is described. The wall system includes wall studs that are coupled together to form a frame and polyisocyanurate insulation boards that are positioned on an exterior side of the frame to form an exterior wall. The polyisocyanurate foam boards include a polyisocyanurate core having a halogen free fire retardant. Wall boards are attached to an interior side of the frame to form an interior wall. The wall boards are free of a halogenated fire retardant. The wall studs, polyisocyanurate foam boards, and wall board define a plurality of wall cavities within which an insulation material is positioned. The insulation material is free of a halogenated fire retardant.

BACKGROUND OF THE INVENTION

Polyisocyanurate foam (i.e., PIR board stock) has been widely used toinsulate roofs and walls of commercial and industrial buildings for manydecades due to its excellent thermal insulation, flame resistance, andmechanical properties. The main reason for its excellent flameresistance is the formation of isocyanurate trimer during the foamingprocess. However, in order to pass the fire tests required by buildingcode, such as the ASTM E-84 test, extra fire retardants are stillneeded. Halogenated fire retardants, such as TCPP(tris(2-chloroisopropyl)phosphate), are commonly used in PIR boardstock. Halogenated fire retardants, especially TCPP, are very effectivefire retardants due to their dual functions of gas phase radicalscavenging and char formation in the solid phase. However, someinsulation specifiers have expressed an interest in using materialswhich do not contain TCPP or other halogenated fire-retardants.

BRIEF SUMMARY OF THE INVENTION

The embodiments described herein provide polyisocyanurate foam products,and particularly polyisocyanurate foam boards, that include anon-halogenated fire retardant. According to one aspect, an insulatedstructure is described. The insulated structure includes a plurality ofstructural support members that are coupled together to form a frame. Aplurality of foam boards are attached to an exterior side of the frameto form an insulative exterior wall or surface of the structure. In someembodiments, the foam boards may be attached to the exterior side of theframe to form a continuous insulative exterior wall. A plurality of wallboards are attached to an interior side of the frame to form an interiorwall or surface of the structure. The structural support members, foamboards, and wall boards are coupled together to define a plurality ofwall cavities.

A plurality of fasteners attach the foam boards and the wall boards tothe respective sides of the frame. Each fastener includes an elongateshaft that penetrates through a respective board and into a respectivestructural support member to couple the components together. Aninsulation material is positioned within at least one of the wallcavities of the structure, and often within all or most wall cavities.Each or most of the foam boards includes a polyisocyanurate core that isproduced from: an isocyanate, a polyol, and at least one phosphoruscontaining non-halogenated fire retardant. The polyisocyanurate coreforms a sufficiently stable char when exposed to flame conditions inaccordance with an ASTM E-84 that enables the polyisocyanurate core topass the ASTM E-84 test. The polyisocyanurate core foam board alsoexhibits an initial R-value of at least 6.4 and an ASTM E1354-11 bperformance that is equivalent with or better than a similarpolyisocyanurate foam board having a halogenated fire retardant, such astris(2-chloroisopropyl)phosphate (TCPP).

In some embodiments, the polyisocyanurate core also includes between 1and 10 weight percent of a hydrocarbon blowing agent. Each foam boardmay further include a foil facer that is attached to an exterior side ofthe foam board. The polyisocyanurate core may have an isocyanate indexof greater than 200. The insulation material that is positioned withinat least one of the wall cavities may be a spray foam material, afiberglass material, or a combination thereof. An additional wall boardmay be attached to the exterior side of the frame and positioned betweenthe plurality of foam boards and the frame.

The phosphorus containing non-halogenated fire retardant may include anorgano-phosphate, an organo-phosphite, an organo-phosphonate, or acombination thereof. The phosphorous containing non-halogenated fireretardant may be isocyanate reactive. In an exemplary embodiment, thephosphorous containing non-halogenated fire retardant may be diethylhydroxymethyl phosphonate (DEHMP). The polyisocyanurate core may have anaverage foam cell size of no more than 200 microns. Each foam board mayhave a density of between about 1.5 and 2.5 pcf.

According to another aspect, a method of forming a wall of a structureis described. The method includes coupling a plurality of structuralsupport together to form a frame and attaching a plurality of foamboards to an exterior side of the frame to form an insulative exteriorwall or surface. The method also includes attaching a plurality of wallboards to an interior side of the frame to form an interior wall orsurface. These components may be attached or coupled together so thatthe structural support members, foam boards, and wall boards define aplurality of wall cavities. The method further includes positioning aninsulation material within at least one of the wall cavities to insulatean interior space of the structure.

At least one of the foam boards, and commonly most or all foam boards,includes a polyisocyanurate core that is produced from: an isocyanate, apolyol, and at least one phosphorus containing non-halogenated fireretardant. The polyisocyanurate core forms a sufficiently stable charwhen exposed to flame conditions in accordance with an ASTM E-84 thatenables the polyisocyanurate core to pass the ASTM E-84 test. Thepolyisocyanurate core foam board exhibits an initial R-value of at least6.4 and an ASTM E1354-11b performance that is equivalent with or betterthan a similar polyisocyanurate foam board having a halogenated fireretardant, such as tris(2-chloroisopropyl)phosphate (TCPP).

In some embodiments, the method further includes adding between 1 and 10weight percent of a hydrocarbon blowing agent to the polyisocyanuratecore. In some embodiments, the method additionally includes attaching afoil facer to an exterior side of the foam board and/or to an interiorside of the foam board.

According to another aspect, a halogen free wall system is described.The wall system includes a plurality of structural support members thatare coupled together to form a frame and a plurality of polyisocyanurateinsulation wall boards that are positioned on an exterior side of theframe to form an exterior wall or surface. The polyisocyanurate foaminsulation boards have an isocyanate index greater than 200 and includea polyisocyanurate core having a halogen free fire retardant. Thepolyisocyanurate core forms a sufficiently stable char when exposed toflame conditions in accordance with an ASTM E-84 such that thepolyisocyanurate core passes the ASTM E-84 test.

A plurality of wall boards are attached to an interior side of the frameto form an interior wall or surface. The plurality of wall boards arefree of a halogenated fire retardant. The structural support members,foam boards, and wall boards are coupled or attached together to definea plurality of wall cavities. An insulation material is positionedwithin at least one of the wall cavities of the structure and oftenwithin most or all wall cavities. The insulation material is free of ahalogenated fire retardant.

In some embodiments, a plurality of additional wall boards arepositioned on the exterior side of the frame between thepolyisocyanurate insulation wall boards and the frame. The additionalwall boards are free of a halogenated fire retardant. Cladding may alsobe positioned on an exterior side of the polyisocyanurate insulationwall boards. The cladding is free of a halogenated fire retardant. Insome embodiments, the wall board may be dry wall.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described in conjunction with the appendedfigures:

FIG. 1 illustrates an embodiment of a polyisocyanurate foam board.

FIG. 2 illustrates a method of forming a polyisocyanurate foam board.

FIG. 3 illustrates an embodiment of a wall system or structure that maybe used to insulate a commercial or residential structure.

FIG. 4 illustrates a method of forming a wall of a structure.

FIG. 5 illustrates a roof deck or system that may be used for acommercial or industrial structure.

FIG. 6 illustrates a method of forming a roofing system of a structure.

In the appended figures, similar components and/or features may have thesame numerical reference label. Further, various components of the sametype may be distinguished by following the reference label by a letterthat distinguishes among the similar components and/or features. If onlythe first numerical reference label is used in the specification, thedescription is applicable to any one of the similar components and/orfeatures having the same first numerical reference label irrespective ofthe letter suffix.

DETAILED DESCRIPTION OF THE INVENTION

The ensuing description provides exemplary embodiments only, and is notintended to limit the scope, applicability or configuration of thedisclosure. Rather, the ensuing description of the exemplary embodimentswill provide those skilled in the art with an enabling description forimplementing one or more exemplary embodiments. It being understood thatvarious changes may be made in the function and arrangement of elementswithout departing from the spirit and scope of the invention as setforth in the appended claims.

The description and/or claims herein may use relative terms indescribing features and/or aspects of the embodiments. For example, thedescription and/or claims may use terms such as relatively, about,substantially, approximately, and the like. These relative terms aremeant to account for deviations that may be appreciated or accepted inthe art. For example, the description and/or claims may describe thewall or roof system being substantially free of halogen. Such adescription implies that each or most of the wall system components isfree of a halogen fire retardant while recognizing the some of thecomponents may include a very small and/or negligible amount of halogen.Likewise, the disclosure herein may describe the components of the wallor roof system being substantially continuous. Such a descriptionimplies that the components may be assembly and/or attached so that alayer of the component or material is essentially continuous whilerecognizing that some interruptions from a fully continuous surface orlayer, or other minor irregularities, may be present. The relative termsused herein may account for deviations from uniform that may appreciatedand/or accepted by those skilled in the art. These deviations may be upto about 10%, but are typically less than 5% and often less than about3%.

The embodiments described herein provide polyisocyanurate foam products,and particularly polyisocyanurate foam boards, that include anon-halogenated fire retardant. The embodiments described herein alsoprovide wall and roofing systems that include the polyisocyanurate foamproducts. The embodiments demonstrate similar or better fireperformances in ASTM E-84 and/or ASTM E1354 tests when compared tosimilar foam products that contain a halogenated fire retardant (e.g.,tris(2-chloroisopropyl)phosphate (TCPP)). In some embodiments, thepolyisocyanurate foam may be a polyurethane modified polyisocyanuratedue to the presence of urethane/urea linkages in the foam.

Exemplary polyfunctional isocyanates that may form substituted orunsubstituted polyisocyanates that are used to make the polyisocyanuratefoam boards and other foam products include aromatic, aliphatic, andcycloaliphatic polyisocyanates having at least two isocyanate functionalgroups. Exemplary aromatic polyfunctional isocyanates include:4,4′-diphenylmethane diisocyanate (MDI), polymeric MDI (PMDI), toluenedisisocyanate, and allophanate modified isocyanate. For example, thepolyfunctional isocyanate may be PMDI with functionality between 2.3 to3.0, viscosity less at 800 cps at 25, and isocyanate content between 28%to 35%.

The polyfunctional isocyanates may be reacted with a polyfunctionalco-reactant that has at least two reactive groups that react with thepolyfunctional isocyanate to produce a polyisocyanurate compounds forthe present products. Exemplary polyfunctional co-reactants may includepolyester and polyether polyols having at least 2 isocyanate reactivegroups, such as hydroxyl groups. Specific examples include aromaticpolyester polyols which have good mechanical properties, as well ashydrolytic and thermo-oxidative stability. Commercially availablepolyester polyol include those sold by Stepan Company under the nameStepanol® and those sold by Huntsman Corporation under the name ofTerol®. Exemplary polyols may have a functionality between 2 and 2.5 andhydroxyl number between 150 mg KOH/gm and 450 mg KOH/gm.

The catalysts used to polymerize the polyisocyanurates may include aminecatalysts and metal catalysts, among other catalysts. The aminecatalysts catalyze both urethane reactions between isocyanates andpolyols, and urea reactions between water and isocyanates. The metalcatalysts may include metal carboxylate trimer catalysts, which promotethe conversion of isocyanate to highly thermally stable isocyanuratering. Examples of suitable amine catalysts includepentamethyldiethylenetriamine (PMDETA), dimethylcyclohexylamine, and1,3,5-tris(3-(dimethylamino)propyl)-hexahydro-triazine. Examples ofsuitable metal catalysts include potassium octoate and potassiumacetate.

The present polyisocyanurate formulations may also include one or moresurfactants. The surfactants function to improve compatibility of theformulation components and stabilize the cell structure during foaming.Exemplary surfactants can include organic or silicone based materials.Typical silicone based surfactants may include polyether modifiedpolysiloxane, such as commercially available DC193 surfactant fromAirProducts, and Tergostab® series surfactants from Evonik, such asTergostab® 8535.

The ASTM E-84 tunnel test is a common fire test that is required forplastic foam insulation boards used in either wall or roof insulationsystems. The test requires removing any facer products from theinsulation boards and measuring the flame spread and smoke density thatis generated by the foam core in response to exposure to a flame. Mostpolyurethane/polyisocyanurate foam insulation boards can only pass thistest by using halogenated fire retardants. The halogenated fireretardants enable the insulation boards to pass this test due to thefire retardants dual function of gas phase radical scavenging and charformation in the solid phase.

It is therefore surprising to discover that the polyisocyanurate foaminsulation boards described herein that include a non-halogenated fireretardant exhibit a similar or better fire-retardant performance inrelation to the ASTM E-84 and ASTM E1354-11 b tests than conventioninsulation boards that include a halogenated fire retardant (e.g.,TCPP). The observed increase in fire-retardant performance may be due toan ability of the polyisocyanurate foam insulation forming asufficiently stable char such that the use of a halogenated fireretardant becomes unnecessary. The non-halogenated fire retardants usedin the embodiments described herein may be blend of organa phosphoruscompounds including: organo-phosphate, organo-phosphite, and/ororgano-phosphonate. The non-halogenated organa phosphorus fire retardantcould be non-reactive or reactive, i.e. containing isocyanate reactivefunctionality. An exemplary non-reactive organa phosphorus fireretardant is a blend of butyl diphenyl phosphate, dibutyl phenylphosphate, and triphenyl phosphate. An exemplary reactive organphosphorus fire retardant is diethyl hydroxylmethyl phosphonate (DEHMP).

Exemplary Foam Boards

Referring now to FIG. 1, illustrated is an embodiment of apolyisocyanurate foam board 100 (hereinafter foam board 100). The foamboard 100 includes a polyisocyanurate core 102 that is produced from anisocyanate, a polyol, and at least one phosphorous containingnon-halogenated fire retardant (e.g., a non-halogenated isocyanatereactive phosphorus compound).

The polyol typically includes either or both a polyether and polyesterhaving a hydroxyl number between about 25 and 500, and more commonlybetween about 200 and 270. The hydroxyl number is a measure of theconcentration of the hydroxyl group in the polyol, which is expressed asthe milligrams of KOH (potassium hydroxide) equivalent to the hydroxylgroups in one gram of polyol. Polyether is commonly not used inconventional polyisocyanurate foam boards because it is typically lessflame resistant than the aromatic polyester that is used in such boards.A lower hydroxyl number commonly results in longer polymer chains and/orless cross linking, which results in a relatively loose polymer chain.In contrast, a higher hydroxyl number commonly results in more crosslinking and/or shorter polymer chains, which may provide enhancedmechanical properties and/or flame resistance.

The polyisocyanurate core 102 has an isocyanate index greater than about200, commonly between about 200 and 300, and more commonly between about250 and 270. When isocyanate reacts with one or more polyols to formpolyurethane, one NCO group reacts with one OH group. As is known in theart, the index is defined as the ratio of NCO group to OH groupmultiplied by 100 as shown in the formula below:

${Index} = {\frac{{Moles}\mspace{14mu}{of}\mspace{14mu}{NCO}\mspace{14mu}{group}}{{Moles}\mspace{14mu}{of}\mspace{14mu}{OH}\mspace{14mu}{group}} \times 100}$

When the number of NCO group equals the number of OH group in aformulation, a stoichiometric NCO:OH ratio of 1.0 is realized and apolyurethane polymer/foam is produced. When the number of NCO groups issignificantly more than the number of OH groups in a formulation, theexcess isocyanate group reacts with itself under catalytic condition toform isocyanurate linkage and polyisocyanurate foam is produced. Theabove described isocyanate index, and especially an index of betweenabout 250 and 270, provides at least a 2:1 ratio of NCO groups to OHgroups, which has been found to provide an appreciable combination ofstructure integrity, thermal strength and/or stability, and fireresistance.

The above described index values also typically require less fireretardant materials to be used to enable passing of the ASTM E-84 and/orASTM E1354-11 b tests. For example, conventional polyisocyanurate foaminsulation boards having an isocyanate index of less than 200 commonlyrequire the application or use of significantly more fire retardantmaterials to enable these products to pass the ASTM E-84 and/or ASTME1354-11 b tests. In some embodiments, the polyisocyanurate core 102 mayinclude between about 2 and 5 weight percent of the phosphorouscontaining non-halogenated fire retardant. Conventional polyisocyanurateboards typically include between about 3 to 4% of a halogenated fireretardant, such as TCPP.

In some embodiments, the non-halogenated phosphorus containing fireretardant is isocyanate reactive. In some embodiments, the phosphorouscontaining non-halogenated fire retardant includes: an organo-phosphate,an organo-phosphite, and/or an organo-phosphonate. In an exemplaryembodiment, the phosphorous containing non-halogenated fire retardantincludes diethyl hydroxymethyl phosphonate (DEHMP). In otherembodiments, the phosphorous containing non-halogenated fire retardantmay include: dialkyl hydroxyalkanephosphonate (e.g., dimethylhydroxymethylphosphonate), diaryl hydroxyalkanephosphonate (e.g.,diphenyl hydroxymethylphosphonate), and the like.

The polyisocyanurate core is able to form a sufficiently stable charwhen exposed to flame conditions in accordance with an ASTM E-84 thatenables the polyisocyanurate core to pass the ASTM E-84 test. Thenon-halogenated phosphorus compound promotes charring in the solidphase, which reduce the fuel supply to the flame and effectivelydecrease the temperature of the flame that may further decompose thepolymer. The polyisocyanurate core 102 typically has an average foamcell size of less than about 200 microns, and more commonly betweenabout more commonly 100-150. In contrast, conventional foam boardstypically have an average foam cell size of between about 200 and 300.The smaller foam cell size of the polyisocyanurate core 102 may enablethe resulting foam board to exhibit an increased R-value when comparedwith conventional foam boards.

In some embodiments, the polyisocyanurate core 102 may include between 1and 10 weight percent of a hydrocarbon blowing agent, such as n-pentane,iso-pentane, cyclopentane, and their blends. In an exemplary embodiment,the polyisocyanurate core 102 may include between 5 and 8 weight percentof the hydrocarbon blowing agent. The weight percent of the hydrocarbonblowing agent typically corresponds with the foam density of thepolyisocyanurate core 102 with lower density foam boards (e.g.,insulation boards) having a higher weight percentage of the hydrocarbonblowing agent than more dense foam boards (e.g., roofing cover boards).For example, insulation boards having a density of between about 1.5 and2.5 pounds per cubic foot (lbs/ft³), commonly have 5% or more of ahydrocarbon blowing agent by weight, and more commonly between about 6and 7 weight percent. In contrast, roofing cover boards that have adensity of up to 10 lbs/ft³, and more commonly between 6 and 7 lbs/ft³,commonly have less than 5% of a hydrocarbon blowing agent by weight, andmore commonly between about 1.5 and 3 weight percent.

Hydrocarbon blowing agents, such as n-pentane, iso-pentane,cyclopentane, and their blends, are extremely flammable materials (i.e.,materials that commonly have a Lower Explosive Limit (LEL) of less than2% in air) that negatively contribute to a polyisocyanurate foam board'sfire resistance. For example, n-pentane, isopentane, and cyclopentanehave LEL values of 1.5%, 1.4%, and 1.1% at 20° C. and 1 atmosphere ofpressure, respectively. Stated differently, the hydrocarbon blowingagents typically reduce the fire resistance of the polyisocyanurate foamboard by providing a fuel source that feeds a fire. As a result,conventional polyisocyanurate foam boards that use hydrocarbon blowingagents are typically unable to pass the ASTM E-84 and/or ASTM E1354-11 btests without the use of halogenated fire retardants. Some conventionalpolyisocyanurate foam boards that do not require a halogenated fireretardant have passed the above tests, but are only able to do so bygreatly reducing the amount of hydrocarbon blowing agents used and/or byusing alternative blowing agents that are significantly less flammable.Hydrocarbon blowing agents are typically less expensive and offer a goodthermal insulation value. Other blowing agents, such as Methyl Formate,are commonly more expensive and/or pose other problems, such as theformation of formic acid (i.e., from Methyl Formate), which may presentproblems associated with corrosion.

In some embodiments, the polyisocyanyurate foam boards described hereinonly include or use an extremely/highly flammable hydrocarbon agent,such as those described above. Stated differently, the polyisocyanyuratefoam boards do not include or use alternative blowing agents that aresignificantly less flammable and/or do not include or use a combinationof an extremely flammable hydrocarbon agent and a less flammablealternative blowing agent. The alternative less flammable blowing agentsmay include one or more materials or components having a relativelysignificant ozone depleting potential. As such, these blowing agents maycontribute to global warming to a greater degree than theextremely/highly flammable hydrocarbon agents and therefore, may be lessdesirable despite their decreased flammability. In some embodiments, thepolyisocyanyurate foam boards described herein substantially include oruse an extremely flammable hydrocarbon agent, such as those describedabove, but may have some insignificant or minor amount of anothermaterial that may be considered a less flammable alternative blowingagent.

In contrast to these conventional systems, the phosphorous containingnon-halogenated fire retardants described herein (e.g., DEHMP), enablethe resulting polyisocyanurate foam boards to pass the ASTM E-84 and/orASTM E1354-11 b tests even when a substantial amount of a highlyflammable hydrocarbon blowing agent is used—e.g., a blowing agent havingan LEL of less than 2% in air. In some embodiments, the blowing agentused may only or substantially include a highly flammable hydrocarbonblowing agent (e.g., a blowing agent having an LEL of less than 2% inair), although in other embodiments the blowing agent used may be acombination of a highly flammable hydrocarbon blowing agent and a lessflammable hydrocarbon blowing agent.

The above blowing agents may be used regardless of the foam density ofthe resulting polyisocyanurate foam board. For example, a lower densityfoam insulation board (i.e., foam density of between 1.5 and 2.5lbs/ft³, and more commonly between 1.6 and 1.8 lbs/ft³) may include ablowing agent that only includes a highly flammable hydrocarbon blowingagent (e.g., a blowing agent having an LEL of less than 2% in air), ormay include a combination of a highly flammable hydrocarbon blowingagent and a less flammable hydrocarbon blowing agent. A higher densityfoam cover board (i.e., foam density of up to 10 lbs/ft³, and morecommonly between 6 and 7 lbs/ft³) may likewise include a blowing agentthat only includes a highly flammable hydrocarbon blowing agent (e.g., ablowing agent having an LEL of less than 2% in air), or may include acombination of a highly flammable hydrocarbon blowing agent and a lessflammable hydrocarbon blowing agent.

Foam board 100 also includes a facer material 104 that is applied to atleast one surface of the polyisocyanurate core 102. The facer material104 typically includes a glass fiber mat, but may include other types offacer materials. The facer material 104 is typically selected based onthe type of polyisocyanurate foam board produced. For example, facersfor polyisocyanurate foam insulation boards that are used in roofingapplications may include: a reinforced cellulosic felt facer, anun-coated polymer bonded glass fiber mat, a coated polymer bonded glassfiber mat, and the like. In such embodiments, the facer 104 may includea mineral and/or pigment based coating with high solid content toprovide one or more desired characteristics, such as low porosity, fireretardancy, mechanical strength, and the like. The facer 104 may have athickness of between about 0.3 and 1.2 mm.

Facers for polyisocyanurate foam cover boards that are used in roofingapplications may include: coated polymer bonded glass fiber mat, whichprovides desired characteristics, such as low porosity, fire retardancy,mechanical strength, and the like. In such embodiments, the facer 104may have a thickness of between about 0.4 and 1.2 mm. Facers forpolyisocyanurate foam boards that are used in wall applications mayinclude a metal foil facer that is configured to reflect heat, such asfrom and/or into a structure, and/or may include an un-coated polymerbonded glass mat, coated polymer bonded glass mat, and the like. In suchembodiments, the facer 104 may have a thickness of between about 0.006and 1.2 mm. The thickness of 0.006 mm typically represents the thicknessof a metal facer while the 1.2 mm represents the thickness of otherfacers.

Although FIG. 1 shows the facer 104 being positioned on a single side ofthe polyisocyanurate core 102, it should be realized that in manyembodiments an additional facer may be positioned on the opposite sideof the polyisocyanurate core 102. The additional facer may be a similaror different facer than facer 104 and/or may have a different thicknessand/or material coating as desired.

As briefly mentioned above, the polyisocyanurate foam board 100 has aninitial R-value of at least 6.40, and commonly between 6.5 and 6.55.This initial R-value is higher than that initially exhibited byconventional polyisocyanurate foam boards. For example, conventionalfoam boards typically have an initial R-value of about 6.3 and notnormally greater than 6.4. As such, the polyisocyanurate foam boardcomposition of the embodiments described herein provide an initialR-value increase of approximately 0.01 to 0.15. The increase in R-valueof the polyisocyanurate foam boards described herein may be achievedthrough a nucleation effect that results in smaller cell size in thefoam as described above.

In addition, as described herein, the polyisocyanurate foam board 100exhibits an ASTM E1354-11 b performance equivalent with or better than asimilar polyisocyanurate foam board having a halogenated fire retardant,such as tris(2-chloroisopropyl)phosphate (TCPP). The polyisocyanuratefoam board 100 commonly has a density of between about 1.45 and 10lbs/ft³, and more commonly between 1.5 and 7.5 lbs/ft³. In an exemplaryembodiment, a polyisocyanurate foam cover board may have a density ofbetween about 4 and 8 lbs/ft³, and more commonly between about 6 and 7lbs/ft³; a polyisocyanurate foam insulation roofing board may have adensity of between about 1.5 and 2.0 lbs/ft³, and more commonly betweenabout 1.6 and 1.7 lbs/ft³; and a polyisocyanurate foam sheathing boardmay have a density of between about 1.5 and 2.5 lbs/ft³, and morecommonly between about 1.6 and 2.0 lbs/ft³.

Referring now to FIG. 2, illustrated is a method of forming apolyisocyanurate foam board. At block 210, a polyol is provided. Atblock 220, an isocyanate is added to the polyol to form apolyisocyanurate core having an isocyanate index greater than about 200.At block 230, a non-halogenated phosphorous containing fire retardant isadded to the polyisocyanurate core. As described herein, the compositionof the polyisocyanurate foam board enables the polyisocyanurate core toform a sufficiently stable char when exposed to flame conditions inaccordance with an ASTM E-84 such that the polyisocyanurate core passesthe ASTM E-84 test. At block 240, a facer material is coupled with atleast one surface of the polyisocyanurate core. The facer materialincludes a glass fiber mat, or other mat, that may be selected based onthe end application of the polyisocyanurate foam board as describedherein. In some embodiments, an additional facer material may be coupledwith an opposite surface of the polyisocyanurate core.

The resulting polyisocyanurate foam board may have an R-value of atleast 6.40 and may exhibit an ASTM E1354 Cone calorimeter testperformance that is equivalent with or better than a similarpolyisocyanurate foam board having a halogenated fire retardant, such astris(2-chloroisopropyl)phosphate (TCPP). In some embodiments, the methodmay also include adding between 1 and 10 weight percent of a hydrocarbonblowing agent to the polyisocyanurate foam board.

Exemplary Wall Systems

Wall structures or systems of commercial and residential structures arecommonly insulated by filling a wall cavity that is positioned betweenwall studs (wood or metal). The wall cavity may be filled using a sprayfoam insulation (open cell and/or close cell), Batt or roll insulation(e.g., fiberglass, mineral wool, cotton, and the like), loose fillinsulation (e.g., fiberglass, cellulose, mineral wool, and the like), ora combination thereof. Thermal bridging from the wall studs can reducethe effectiveness of the cavity insulation. To reduce the effects ofthermal bridging, the wall system or structure may include externalsheathing insulation (e.g., continuous external sheathing), such as witha foil faced rigid polyisocyanurate foam board, that is coupled with thecavity insulation.

Referring now to FIG. 3, illustrated is an embodiment of a wall systemor structure 300 that may be used to insulate a commercial orresidential structure. In some embodiments, wall system 300 may be asubstantially halogen free wall system, wherein each or most of the wallsystem components is free of a halogen fire retardant. Wall system 300includes a plurality of structural support members or wall studs 302that are coupled together to form a wall frame. A plurality of foamboards 304 (hereinafter sheathing boards 304) are attached to anexterior side of the frame to form an insulative exterior wall orsurface of the wall system 300 (i.e., continuous external sheathinginsulation). A plurality of wall boards 306 are attached to an interiorside of the frame opposite the sheathing boards 304 to form an interiorwall or surface of the wall system 300. In some embodiments, the wallboards 306 are free of a halogenated fire retardant. Exemplary wallboards 306 include gypsum boards and the like. The wall studs 302,sheathing boards 304, and wall boards 306 define a plurality of wallcavities 308.

Fasteners (not shown) are used to attach the sheathing boards 304 andwall boards 306 to the respective sides of the frame. Each fastener mayinclude an elongate shaft that penetrates through a respective board andinto a wall stud 302 to couple the components together. Exemplaryfasteners include nails and screws, although in some embodimentsnon-mechanical fasteners may be used, such as adhesives and the like. Aninsulation material 310 is positioned within at least one of the wallcavities 308 of the wall system, and more commonly within each wallcavity 308 or within most of the wall cavities. The insulation material310 is positioned within the wall cavity 308 to insulate the building orstructure. As described herein, exemplary insulation materials includespray foam insulation (open cell and/or close cell), Batt or rollinsulation (e.g., fiberglass, mineral wool, cotton, and the like), loosefill insulation (e.g., fiberglass, cellulose, mineral wool, and thelike), or a combination thereof. In some embodiments, the insulationmaterial may be free of a halogenated fire retardant.

In some embodiments, an additional wall board 312 may be attached to theexterior side of the frame. In some embodiments, the additional wallboard 312 may be free of a halogenated fire retardant. The additionalwall board 312 may be a gypsum board, cement board, oriented strandboard (OSB), plywood, and the like. Wall board 312 may be positionedbetween the sheathing board 302 and frame or wall studs 302 forstructural support and/or other purposes. External veneer or cladding314 (hereinafter exterior cladding 314) may be positioned on an exteriorside of the sheathing boards 304. In some embodiments, the exteriorcladding 314 may be free of a halogenated fire retardant. The exteriorcladding 314 may include brick, stucco, rock, siding, paneling, and thelike that provides the structure with an aesthetic appeal whileoptionally also providing one or more desired mechanical or othercharacteristics. In some embodiments, a drainage cavity or barrier maybe positioned between one or more of the components of the wall system,such as between the exterior cladding 314 and the sheathing boards 304.The wall system 300 may also include other components, layers, and/ormaterials that are not shown, such as an interior vapor barrier,flashing, primer, and the like.

As described herein, the sheathing board 304 of wall system 300 includea polyisocyanurate core that is produced from: an isocyanate, a polyol,and at least one phosphorus containing non-halogenated fire retardant(e.g., DEHMP). The polyisocyanurate core has an isocyanate index ofgreater than 200. The polyisocyanurate core composition or formulationenables the polyisocyanurate core to form a sufficiently stable charwhen exposed to flame conditions in accordance with an ASTM E-84. Thisenables the polyisocyanurate core to pass the ASTM E-84 test. Thepolyisocyanurate core foam board also exhibits an initial R-value of atleast 6.4, and commonly 6.5 to 6.55, and further exhibits an ASTME1354-11b test performance that is equivalent with or better than asimilar polyisocyanurate foam sheathing board having a halogenated fireretardant, such as tris(2-chloroisopropyl)phosphate (TCPP).

In some embodiments, the sheathing board 304 may also include a foilfacer that is attached to an exterior side of the board. The sheathingboards 304 may have a foam density of between about 1.5 and 2.5 lbs/ft³,and more commonly between about 1.6 and 2.0 lbs/ft³. In someembodiments, the polyisocyanurate core also include between 1 and 10weight percent of a hydrocarbon blowing agent, which may be a highlyflammable material as described herein above. The sheathing board morecommonly include between about 5 and 8 weight percent of the hydrocarbonblowing agent.

Referring now to FIG. 4, illustrates is a method of forming a wall of astructure. At block 410, a plurality of structural support (i.e., wallstuds) are coupled together to form a frame. At block 420, a pluralityof foam boards (i.e., polyisocyanurate sheathing boards) are attached toan exterior side of the frame to form an insulative exterior wall orsurface. At block 430, a plurality of wall boards are attached to aninterior side of the frame to form an interior wall or surface. Thestructural support members, foam boards, and wall boards are coupledtogether to define a plurality of wall cavities. At block 440, aninsulation material (e.g., a spray foam material, a fiberglass material,or a combination thereof) is positioned within at least one of the wallcavities, and commonly most or all wall cavities, to insulate aninterior space of the structure.

As described herein, at least one of the foam board includes apolyisocyanurate core that is produced from: an isocyanate, a polyol,and at least one phosphorus containing non-halogenated fire retardant.The polyisocyanurate core is configured to form a sufficiently stablechar when exposed to flame conditions in accordance with an ASTM E-84that enables the polyisocyanurate core to pass the ASTM E-84 test. Thepolyisocyanurate core foam board has an initial R-value of at least 6.4and exhibits an ASTM E1354-11 b performance that is equivalent with orbetter than a similar polyisocyanurate foam sheathing board having ahalogenated fire retardant, such as tris(2-chloroisopropyl)phosphate(TCPP).

In some embodiments, the method also includes applying between 1 and 10weight percent of a hydrocarbon blowing agent to the polyisocyanuratecore. In some embodiments, the method further includes attaching a foilfacer to an exterior side of the polyisocyanurate core.

Exemplary Roofing Systems

Commercial and industrial roofing system usually include a combinationof layers, such as an insulation layer and a waterproof layer. In someinstances, a cover board can be used between the insulation layer andwaterproof layer to add fire and/or mechanical protection, such as hailresistance. According to the embodiments herein, a roofing system'sinsulation layer for commercial and/or industrial roofing includespolyisocyanurate foam boards. The waterproof layer includes a built-uproof, modified bitumen, and/or a single ply membrane, such asthermoplastic olefin (TPO), polyvinyl chloride (PVC), ethylene propylenediene monomer (EPDM), metal, and the like.

Referring now to FIG. 5, a construction of a commercial roof deck (i.e.,roof system 500) is shown. In some embodiments, roof system 500 may be asubstantially halogen free system, wherein each or most of the roofsystem components is free of a halogen fire retardant. Roof system 500includes a structural deck 502, which is commonly made of steel orgalvanized metal (18 to 22 gauge), although other types of materialsand/or sizes are possible. The structural deck 502 is commonlypositioned above steel, metal, or other joists and supported thereby. Aplurality of foam insulation boards 504 (hereinafter insulation boards504) are positioned atop the structural deck 502 to form an insulativelayer of roofing system 500. As described herein, the insulation boards504 are polyisocyanurate foam boards having an isocyanate index greaterthan 200.

In some embodiments, a plurality of cover boards 506 are positioned atopthe insulation boards 504 to add a protective layer to roofing system500. The covers board 506 may be added for fire and/or mechanicalprotection (e.g., hail or impact resistance) or for various otherreasons. In some embodiments, the cover boards 506 are free of ahalogenated fire retardant. As described herein, in some embodiments,the cover boards 506 may include a halogen free high densitypolyisocyanurate foam board. In other embodiments, the cover boards 506may include perlite based boards, gypsum based boards, and the like. Insome embodiments, the roofing system 500 does not include cover boards506.

A water proof membrane 508 is positioned atop the roofing system 500.The water proof membrane 508 may be positioned atop the cover boards506, insulation boards 504, and/or another component/layer of theroofing system 500. In some embodiments, the water proof membrane 508 isfree of a halogenated fire retardant. In such embodiments, the waterproof membrane 508 may include a built-up roof, modified bitumen,thermoplastic olefin (TPO), ethylene propylene diene monomer (EPDM),metal, and the like. The water proof membrane 508 may be ballasted,adhered, mechanically fastened, and the like atop the roofing system 500to couple the water proof membrane 508 with the roofing system'scomponents/layers. Further, individual components of the water proofmembrane 508 may be coupled together to form the water proof membrane508. For example, individual TPO segments, sheets, or strips may be heatwelded together to form a substantially continuous TPO layer atop theroofing system 500. Similarly, individual EPDM segments may be adheredor bonded together and metal segments may be mechanically fastened orbonded to form a substantially continuous water proof membrane layer.

The roofing system 500 may be slightly sloped to promote drainage ofwater and/or for various other reasons as desired. The roof system 500may also include other components, layers, and/or materials that are notshown, such as bonding cement, primer, acoustic infills, and the like.

As described herein, the insulation boards 504 and/or cover boards 506are polyisocyanurate foam boards that include a polyisocyanurate corehaving a halogen free fire retardant. The polyisocyanurate core is ableto form a sufficiently stable char when exposed to flame conditions inaccordance with an ASTM E-84 such that the polyisocyanurate core is ableto pass the ASTM E-84 test. The polyisocyanurate core is produced from:an isocyanate, a polyol, and at least one phosphorus containingnon-halogenated fire retardant (e.g., DEHMP). The polyisocyanurate corehas an isocyanate index of greater than 200. The insulation boards 504also exhibits an initial R-value of at least 6.4 and further exhibit anASTM E1354-11b test performance that is equivalent with or better than asimilar polyisocyanurate foam insulation roofing board having ahalogenated fire retardant, such as tris(2-chloroisopropyl)phosphate(TCPP).

In some embodiments, the insulation boards 504 also includes a facerthat is coupled with one or more surfaces of the insulation board 504,commonly both surfaces. The facer typically includes a glass fiber mat,but may include other types of facer materials. The facer may include: areinforced cellulosic felt facer, an un-coated polymer bonded glassfiber mat, a coated polymer bonded glass fiber mat, and the like. Thefacer may be coated or uncoated as desired to provide a desiredcharacteristic, such as fire retardancy, mechanical strength, and thelike. The insulation board 504 may have a foam density of between about1.5 and 2.0 lbs/ft³, and more commonly between about 1.6 and 1.7lbs/ft³. In some embodiments, the insulation board's polyisocyanuratecore also includes between 1 and 10 weight percent of a hydrocarbonblowing agent, which may be a highly flammable material as describedherein above. The insulation boards 504 commonly include between about 5and 8 weight percent of the hydrocarbon blowing agent.

In some embodiments, the cover boards 506 also includes a facer that iscoupled with one or more surfaces of the cover board 506, commonly bothsurfaces. The facer typically includes a glass fiber mat, but mayinclude other types of facer materials. The cover board 506 may have afoam density of between about 3 and 8 lbs/ft³, and more commonly betweenabout 6 and 7 lbs/ft³. In some embodiments, the cover board'spolyisocyanurate core also includes between 1 and 10 weight percent of ahydrocarbon blowing agent, which may be a highly flammable material asdescribed herein above. The cover boards 506 commonly include betweenabout 1.5 and 3 weight percent of the hydrocarbon blowing agent.

Referring now to FIG. 6, illustrated is a method of forming a roofingsystem of a structure. At block 610, a structural deck is assembled atopjoists (metal and the like) or other structurally supporting members. Atblock 620, a plurality of foam insulation boards (i.e., polyisocyanurateroof insulation boards) are positioned atop the structural deck toprovide an insulation layer for the roofing system. At block 630, aplurality of cover boards are optionally positioned atop the foaminsulation boards to form a protective layer for the roofing system. Atblock 640, a water proof membrane is positioned atop the foam insulationboards and/or cover boards to provide a water proof layer for theroofing system.

As described herein, at least one of the foam insulation boards includesa polyisocyanurate core that is produced from: an isocyanate, a polyol,and at least one phosphorus containing non-halogenated fire retardant.The polyisocyanurate core is configured to form a sufficiently stablechar when exposed to flame conditions in accordance with an ASTM E-84that enables the polyisocyanurate core to pass the ASTM E-84 test. Thepolyisocyanurate core foam board has an initial R-value of at least 6.4and exhibits an ASTM E1354-11 b performance that is equivalent with orbetter than a similar polyisocyanurate foam sheathing board having ahalogenated fire retardant, such as tris(2-chloroisopropyl)phosphate(TCPP).

In some embodiments, at least one of the cover boards includes apolyisocyanurate core that is produced from: an isocyanate, a polyol,and at least one phosphorus containing non-halogenated fire retardant asdescribed herein. In some embodiments, the method also includes applyingbetween 1 and 10 weight percent of a hydrocarbon blowing agent to thepolyisocyanurate core of the foam insulation board(s) and/or coverboard(s). In some embodiments, the method further includes attaching afacer to at least one surface of the foam insulation board(s) and/orcover board(s).

Test Results

A typical non-halogenated reactive phosphorus compound containingpolyisocyanurate foam formulation is shown in Table 1. The resultingpolyisocyanurate foam board is similar to those described herein.

TABLE 1 Non-Halogenated Reactive Phosphorus Compound ContainingPolyisocyanurate Foam Formulation % B-side Chemical Polyester Polyol50-75 Metal Catalysts 4-8 Amine Catalyst 0.1-0.5 DEHMP  6-12 Water0.1-0.3 Pentane 10-25 A-side Chemical Polyisocyanate 100 Index 200-350

The physical properties of the non-halogenated reactive phosphoruscompound containing polyisocyanurate foam, especially DEHMP, are shownin Table 2. Table 2 shows a control sample that is a polyisocyanuratefoam containing a halogenated fire retardant (i.e., TCPP), and also showthree sample polyisocyanurate foams containing a phosphorous containingnon-halogenated fire retardant (i.e., DEHMP): one containing 3% DEHMP,one containing 3.5% DEHMP, and one containing 4.5% DEHMP. The resultsclearly demonstrate that the addition of DEHMP improves the thermalinsulation value (R-value) of the polyisocyanurate foam, likely throughcell size reduction. It is believed that the DEHMP is acting as anucleating agent that minimizes the cell size of the foam.

TABLE 2 Physical Properties of Non-Halogenated Reactive PhosphorusCompound Containing Polyisocyanurate Foam Density Compressive Cell SizeR-Value Sample # (pcf) strength (psi) (μm) (initial) Control 1.59 23 1406.39 4.5% TCPP Trial 1 1.66 23 6.54 3% DEHMP Trial 2 1.65 23 6.54 3.5%DEHMP Trial 3 1.66 24 115 6.51 4.5% DEHMP

The ASTM E-84 test results are shown in Table 3, which clearlydemonstrates that the DEHMP containing polyisocyanurate foams achievesimilar or better fire performance than a similar polyisocyanurate foamcontaining a TCPP fire retardant at the same or lower loading in E-84tests. In some instances (e.g., smoke development index), theperformance of the polyisocyanurate foams containing DEHMP wassubstantially better than the similar polyisocyanurate foam includingthe TCPP fire retardant. For example, the second trial containing 3.5%DEHMP exhibited roughly half the smoke development when compared withthe control sample containing 4.5% TCPP. The flame spread in thepolyisocyanurate foams containing DEHMP was also substantially the sameor lower than the exhibited flame spread of the control sample.

TABLE 3 ASTM E-84 Test Results Density E-84 Flame E-84 Smoke Sample #(pcf) Spread Index Development Index Control 1.59 34 256 4.5% TCPP Trial1 1.66 32 215 3% DEHMP Trial 2 1.65 35 122 3.5% DEHMP Trial 3 1.66 30200 4.5% DEHMP

The ASTM E-1354 Cone calorimeter test results are shown in Table 4. Theresults shown in Table 4 clearly demonstrate that the DEHMP containingpolyisocyanurate foams achieve similar or better performance in totalheat release, peak heat release, total smoke, and mass loss, at the sameor lower loading. The results are surprising since they suggests thefree radical scavenging fire retarding function, which halogenated fireretardants provide, can be replaced by improving the char formation andchar stability of the polymer network through a reactive organophosphorus compound. The embodiments described herein focus on the useof non-halogenated reactive organic phosphorus compound in the rigidpolyisocyanurate foam formulation to achieve these desired fireretardant properties instead of using the more conventional halogenatedfire retardants. The formulation also surprisingly improves the initialthermal insulation value of the resulting foam.

TABLE 4 Cone Calorimeter Test Results (ASTM E1354) Total Heat AverageHeat Peak Heat Total Mass Release Release Release Smoke Loss Sample #(MJ/m²) (kW/m²) (kW/m²) (m²/m²) (%) Control 4 70 113 115 46 4.5% TCPPTrial #1 4 68 120 107 54 3% DEHMP Trial #2 5 59 107 101 52 3.5% DEHMPTrial #3 4 63 103 91 46 4.5% DEHMP

Having described several embodiments, it will be recognized by those ofskill in the art that various modifications, alternative constructions,and equivalents may be used without departing from the spirit of theinvention. Additionally, a number of well-known processes and elementshave not been described in order to avoid unnecessarily obscuring thepresent invention. Accordingly, the above description should not betaken as limiting the scope of the invention.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimits of that range is also specifically disclosed. Each smaller rangebetween any stated value or intervening value in a stated range and anyother stated or intervening value in that stated range is encompassed.The upper and lower limits of these smaller ranges may independently beincluded or excluded in the range, and each range where either, neitheror both limits are included in the smaller ranges is also encompassedwithin the invention, subject to any specifically excluded limit in thestated range. Where the stated range includes one or both of the limits,ranges excluding either or both of those included limits are alsoincluded.

As used herein and in the appended claims, the singular forms “a”, “an”,and “the” include plural referents unless the context clearly dictatesotherwise. Thus, for example, reference to “a process” includes aplurality of such processes and reference to “the device” includesreference to one or more devices and equivalents thereof known to thoseskilled in the art, and so forth.

Also, the words “comprise,” “comprising,” “include,” “including,” and“includes” when used in this specification and in the following claimsare intended to specify the presence of stated features, integers,components, or steps, but they do not preclude the presence or additionof one or more other features, integers, components, steps, acts, orgroups.

What is claimed is:
 1. An insulated structure comprising: a plurality ofstructural support members coupled together to form a frame; a pluralityof polyisocyanurate foam boards attached to an exterior side of theframe to form a continuous insulative exterior wall or surface of thestructure; a plurality of wall boards attached to an interior side ofthe frame to form an interior wall or surface of the structure, whereinthe structural support members, the polyisocyanurate foam boards, andthe wall boards define a plurality of wall cavities; a plurality offasteners that attach the polyisocyanurate foam boards and the wallboards to the respective sides of the frame, wherein each fastenercomprises an elongate shaft that penetrates through a respective boardand into a respective structural support member to couple the componentstogether; and an insulation material that is positioned within at leastone of the wall cavities of the structure; wherein each polyisocyanuratefoam board includes a polyisocyanurate core produced by reactingcomponents that include: an isocyanate; a polyol; and at least onephosphorus containing non-halogenated fire retardant, thepolyisocyanurate core forming a sufficiently stable char when exposed toflame conditions in accordance with an ASTM E-84 that enables thepolyisocyanurate core to pass the ASTM E-84 test, wherein thepolyisocyanurate core foam board comprises an initial R-value of atleast 6.5, and wherein the polyisocyanurate core foam board exhibits anASTM E1354-11b performance equivalent with or better than a similarpolyisocyanurate foam board having a halogenated fire retardanttris(2-chloroisopropyl)phosphate (TCPP); wherein the polyisocyanuratecore comprises an average foam cell size of no more than 200 microns. 2.The insulated structure of claim 1, wherein the polyisocyanurate corefurther comprises between 1 and 10 weight percent of a hydrocarbonblowing agent.
 3. The insulated structure of claim 1, wherein eachpolyisocyanurate foam board further includes a foil facer attached to anexterior side thereof, and wherein the polyisocyanurate core has anisocyanate index of greater than
 200. 4. The insulated structure ofclaim 1, wherein the insulation material that is positioned within theat least one of the wall cavities is a spray foam material, a fiberglassmaterial, or a combination thereof.
 5. The insulated structure of claim1, further comprising an additional wall board that is attached to theexterior side of the frame and positioned between the plurality ofpolyisocyanurate foam boards and the frame.
 6. The insulated structureof claim 1, wherein the at least one phosphorus containingnon-halogenated fire retardant includes one or more of:organo-phosphate; organo-phosphite; or organo-phosphonate.
 7. Theinsulated structure of claim 6, wherein the phosphorous containingnon-halogenated fire retardant is diethyl hydroxymethyl phosphonate(DEHMP).
 8. The insulated structure of claim 1, wherein the phosphorouscontaining non-halogenated fire retardant is isocyanate reactive.
 9. Theinsulated structure of claim 1, wherein each polyisocyanurate foam boardhas a density of between about 1.5 and 2.5 pcf.
 10. A method of forminga wall of a structure comprising: coupling a plurality of structuralsupport together to form a frame; attaching a plurality ofpolyisocyanurate foam boards to an exterior side of the frame to form aninsulative exterior wall or surface; attaching a plurality of wallboards to an interior side of the frame to form an interior wall orsurface, wherein the structural support members, polyisocyanurate foamboards, and wall boards define a plurality of wall cavities; andpositioning an insulation material within at least one of the wallcavities to insulate an interior space of the structure; wherein atleast one polyisocyanurate foam board includes a polyisocyanurate coreproduced by reacting components that include: an isocyanate; a polyol;and at least one phosphorus containing non-halogenated fire retardant,the polyisocyanurate core forming a sufficiently stable char whenexposed to flame conditions in accordance with an ASTM E-84 that enablesthe polyisocyanurate core to pass the ASTM E-84 test, wherein thepolyisocyanurate core foam board comprises an initial R-value of atleast 6.4, and wherein the polyisocyanurate core foam board exhibits anASTM E1354-11b performance equivalent with or better than a similarpolyisocyanurate foam board having a halogenated fire retardanttris(2-chloroisopropyl)phosphate (TCPP); wherein the polyisocyanuratecore comprises an average foam cell size of no more than 200 microns.11. The method of claim 10, wherein the polyisocyanurate core furthercomprises between 1 and 10 weight percent of a hydrocarbon blowingagent.
 12. The method of claim 10, wherein the at least onepolyisocyanurate foam board further includes a foil facer attached to anexterior side thereof, and wherein the polyisocyanurate core has anisocyanate index of greater than
 200. 13. The method of claim 10,wherein the insulation material that is positioned within the at leastone of the wall cavities is a spray foam material, a fiberglassmaterial, or a combination thereof.
 14. The method of claim 10, whereinthe phosphorous containing non-halogenated fire retardant includes oneor more of: organo-phosphate; organo-phosphite; or organo-phosphonate.15. The method of claim 10, wherein the phosphorous containingnon-halogenated fire retardant is diethyl hydroxymethyl phosphonate(DEHMP).
 16. The method of claim 10, wherein the phosphorous containingnon-halogenated fire retardant is isocyanate reactive.
 17. The method ofclaim 10, wherein the at least one polyisocyanurate foam board has adensity of between about 1.5 and 2.5 pcf.
 18. A halogen free wall systemcomprising: a plurality of structural support members coupled togetherto form a frame; a plurality of polyisocyanurate insulation wall boardspositioned on an exterior side of the frame to form an exterior wall orsurface of the wall system, the polyisocyanurate foam insulation boardsbeing produced by reacting an isocyanate and a polyol so that thepolyisocyanurate foam insulation boards have an isocyanate index greaterthan 200, the polyisocyanurate foam insulation boards including apolyisocyanurate core having a halogen free fire retardant, thepolyisocyanurate core forming a sufficiently stable char when exposed toflame conditions in accordance with an ASTM E-84 such that thepolyisocyanurate core passes the ASTM E-84 test, the polyisocyanuratecore comprising an initial R-value of at least 6.5 and an average foamcell size of no more than 200 microns; a plurality of wall boardsattached to an interior side of the frame to form an interior wall orsurface of the wall system, the plurality of wall boards being free of ahalogenated fire retardant, wherein the structural support members, thefoam boards, and the wall boards define a plurality of wall cavities;and an insulation material that is positioned within at least one of thewall cavities of the structure, the insulation material being free of ahalogenated fire retardant.
 19. The halogen free wall system of claim18, further comprising a plurality of additional wall boards that arepositioned on the exterior side of the frame between thepolyisocyanurate insulation wall boards and the frame, the plurality ofadditional wall boards being free of a halogenated fire retardant. 20.The halogen free wall system of claim 19, further comprising claddingpositioned on an exterior side of the polyisocyanurate insulation wallboards, the cladding being free of a halogenated fire retardant.
 21. Thehalogen free wall system of claim 18, wherein the wall board includesdry wall.